What Makes Plants Grow Upward? Light or Gravity?
As we study plants we notice that plants seem to "know" which way to grow. Germinating seedlings emerge above the soil and grow upward. On a window sill, plants turn toward the light. These observations lead to questions such as: 

Why do plants grow upwards? Why do plants grow towards light? Is the growing direction of a plant a response to light or gravity?

 Material and  instructions
Design and perform experiments to test the effects of light and gravity on the direction of plant growth.
Details of this project
More details of this project are available in the members section of ScienceProject.com web site. Since research on this subject has a long history, you might also be able to find good books about it in your local library or find some information on the internet.